Disagreement over this is fierce, sometimes degenerating into ludicrous levels of incivility.
1580s, "want of civilized behavior, rudeness," from French incivilité (early 15c.), from Late Latin incivilitatem (nominative incivilitas), from incivilis "not civil," from in- "not, opposite of" (see in- (1)) + civilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous" (see civil). Meaning "an act of rudeness" is from 1650s. Incivil "not conducive to common good" is from mid-15c.